Referring to FIGS. 1 to 3, description is given hereinafter. Traditionally, a polyethylene sheet called a hole-seal or a service-hole cover (hereinafter referred to merely as a hole-seal) is attached to a door inner panel 1 of an automobile through the intermediary of a sealer (adhesive) 6 in order to ensure watertightness by stopping up access holes 1a formed in the door inner panel 1. The hole-seal is provided to prevent rainwater, and so forth, from making ingress between a door glass 3 and a door outer panel 2 to thereby enter the interior of the automobile through the access holes 1a. 
Further, it has lately been proposed to install a water-noise isolation sheet 4 of a low specific gravity in place of the hole-seal in order to provide noise isolation in addition to watertightness. However, when the peripheral edge of the water-noise isolation sheet 4 is fixed to the door inner panel 1 through the intermediary of the sealer 6 as with the case of the conventional hole-seal, it is not possible to visually recognize the sealer 6 through the peripheral edge of the water-noise isolation sheet 4 because the water-noise isolation sheet 4 is opaque. As a result, a problem arises in that it is not possible to check whether or not the water-noise isolation sheet 4 is accurately bonded to the door inner panel 1 through the intermediary of the sealer 6.
Unless the peripheral edge of the water-noise isolation sheet 4 is reliably bonded to the door inner panel 1 through the intermediary of the sealer 6, there arises a problem that leakage of water and noise occurs, resulting in deterioration of functions of both watertightness and noise isolation.